In Mysql, we can use DO sleep(5) ; to make a pause. But it did not work in Hive.
Is there any sleep function in Hive?
You can call Thread via reflection to make hive wait for some extra time after processing each row, for instance the following query will make hive to wait for 10 seconds
select reflect("java.lang.Thread", "sleep", bigint(10000));
Not the best way but it might work.
Related
Currently, in Databricks if we run the query, it always returns 1000 rows in the first run. If we need all the rows, we need to execute the query again.
In the situations where we know that we need to download full data(1000+ rows), is there a turn around way to execute the query to get all the rows in the first run without re-executing the query?
There should be a down arrow next to the download button which allows you to Download full results. Are you seeing that in your interface? (Source)
I have a sql file running many queries. I want to see the accumualted sum of all queries. I know that if I turn on timing, or call
\timing
query 1;
query 2;
query 3;
...
query n;
at the beginning of the script, it will start to show time it takes for each query to run. However, I need to have the accumulate results of all queries, without having to manually add them.
Is there a systematic way? If not, how can I fetch the interim times to throw them in a variable.
The pg_stat_statements is a good module that provides a means for tracking execution statistics.
First, add pg_stat_statements to shared_preload_libraries in the
postgresql.conf file. To know where this .conf file exists in your
filesystem, run show config_file;
shared_preload_libraries = 'pg_stat_statements'
Restart Postgres database
Create the extension
CREATE EXTENSION pg_stat_statements;
Now, the module provides a View, pg_stat_statements, which helps you to analyze various query execution metrics.
Reset the contents of stat collected before running queries.
SELECT pg_stat_statements_reset();
Now, execute your script file containing queries.
\i script_file.sql
You may get all the timing statistics of all the queries executed. To get the total time taken, simply run
select sum(total_time) from pg_stat_statements
where query !~* 'pg_stat_statements';
The time you get is in milliseconds, which may be converted to desired format using various timestamp related Postgres functions
If you want to time the whole script, on linux or mac you can use the time utility to launch the script.
The measurement in this case is a bit more than the sum of the raw query times, because it includes some overhead of starting and running the psql command. On my system this overhead is around 20ms.
$ time psql < script.sql
…
real 0m0.117s
user 0m0.008s
sys 0m0.007s
The real value is the time it took to execute the whole script, including the aforementioned overhead.
The approach in this answer is a crude, simple client side way to measure the runtime of the overall script. It is not useful to measure milli-second precision server side execution times. It still might be sufficient for many use-cases.
The solution of Kaushik Nayak is a way more precise method to time executions directly on the server. It also provides much more insight into the execution (eg. query level times).
I need to measure the execution time in a query in the ALTIBASE DBMS.
For example, I need to now in ms the time it took a SELECT * FROM example;
I tried to use the methods that have some traditional DBMS like MySQL or Oracle and doesn't work.
There are some method. The first one you can use the log from altibase to analyze. And the other method is to coding some program that recording time from using the SELECT to get result. Now, I also learn to use altibase - We can together.
I found the solution
After entering to the client with next command isql -u sys -p manager -sysdba you need to execute the next query
SET TIMING ON;
Next the following queries will have the execution time.
How to increase sqllab timeout in apache superset? I have tried increasing SUPERSET_TIMEOUT but this does not work. Query gets timedout in 30 secs. I am not able to run a complex query.
See https://superset.incubator.apache.org/faq.html#why-are-my-queries-timing-out for possible reasons for queries to time out, and solutions.
You can modify the time out parameter in File config.py
file path lib/python3.7/site-packages/superset-0.30.1-py3.7.egg/superset
#Timeout duration for SQL Lab synchronous queries
SQLLAB_TIMEOUT = 30
In my case (Superset 0.23.3 on HDP 3.1.0) adding this configuration option to superset_config.py increased the timeout:
SQLLAB_TIMEOUT=120
Also, keep in mind that SUPERSET_TIMEOUT should be equal or greater to the above number, otherwise gunicorn will drop the request before it finishes.
I have a sql query that I need to loop through the system views sys.dm_exec_requests and sys.dm_exec_sessions every 60 seconds to pull specific information and dump it into a separate table. After a specified time I would like it to kill the loop. How would the loop be formatted?
This sounds like a SQL Agent job. If so, the short form of the answer is:
Create the job with one step that runs the query
Add a Schedule that runs it once a minute, starting whenever you want it to start
Set the schedule to stop running it when the cut-off time is reached
The long form, of course, is all the detail work behind creating a SQL Agent job. Best to read up on them in Books Online (here)
Don't do this in a loop. Do it with a job.
Write a sproc that does the query and save the results and then call it from a job.
I think you should use a job as well. But some work environments that is not practical. So you could have something like:
WHILE #StopTime < getdate()
BEGIN
exec LogCurrentData
WAITFOR DELAY '00:01:00'; -- wait 1 minute
END
I think the best way is creating a Job
There is a post that explain how to create a job step by step (with images) in SQL Server.
You can visit the post here
If you prefer a video tutorial, you can visit this link